*{
    margin: 0;
    padding: 0;
}
.nav{
    background-color: blue;
    color: #fff;
}
.courseItem{
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px;
    border-bottom: 1px solid #ccc;
}
.title{
    font-size: 16px;
    font-weight: bold;
}
.teacher{
    font-size: 14px;
    color: #666;
}
.time{
    font-size: 12px;
    color: #999;
}
.courseItem img{
    width: 100px;
    height: 100px;
}
.courseItem div:nth-child(2){
    flex: 1;
}
.futureCourse {
    background-color: rgb(255, 227, 227);
}
.currentCourse {
    background-color: rgb(205, 255, 239);
}
.pastCourse {
    background-color: rgb(226, 226, 226);
}